Synthetic casein fiber elastic grease



United States Patent SYNTHETIC CASEIN FIBER ELASTIC GREASEAmold.J.'Morway,,Rahway, NNL, .and RoherttP. Spray,

Pittsburgh, ;l.a., assignors to Esso Research and Engineering Company,a. corporation of. Delaware No Drawing. Application December 3, 1952,Serial No..323,928=

Claims. (Cl. 252-14) The present invention relates to improvements inelastic fiber greases and particularly to improvements in the elasticityof the fibrous component thereof.

Fiber greases are widely used for packing certain types ofjournalbearings, for example, inrailroad rolling stock.

A relatively large quantity of .such greases isconsumed by industry.Such greases usually'consist primarily of fibrous material such aswool=fiber or yarn impregnated or saturated with an oil or greasecomposition. This lubricant is packed. in a housing in such a way thatit presses against the journal as it revolves and keeps. it

coated with a film of lubricant. The fiber or yarn acts .as areservoirfor the oil or grease and prevents rapid consumption of .the lubricantwhile assuring continuous lubrication.

.ln .thegprior. artwhenthe. fibrous material, usually a reclaimed woolor yarn, has been used aloneincombination with the lubricant it hastended to become mattedrand soggy'and eventually to pull away from thebearing. This is particularly true when the bearings become heated up totemperatures of the order of 200 F.

"The oil rapidly evaporatesand the fibers lose their resistcoarser fibersuch as horse hair, goat hair or other animal hair. The coarser andstiffer hair and thefinerwool fibers are stranded and interspersed witheach other and the entire fibrous mass is thereafter saturated with theoil or grease. While horse hair, in particular, has some utility in thisconnection at ordinary temperatures it is not particularly satisfactoryas temperatures go above 150 F. or so and it is not always available.Horse hair and other animal hair fibers are also susceptible to actualdamage at elevated temperatures and start to decompose and becomebrittle at temperatures as low as 150 to 180 F. They are therefore quiteunsuitable at the moderately high journal and bearing temperaturesfrequently encountered in service, e. g., up to about 200 F. orsometimes a little higher.

According to the present invention it has been discovered that arelatively new type of synthetic fiber consisting of an extruded caseinmonofilament is a particularly suitable material for incorporation inelastic fiber greases which have a tendency to mat and lose contact withthe bearing. This new synthetic fiber of coarse type has considerablygreater elasticity than horse hair or the other coarse animal hairs andin particular it retains its elasticity much longer at moderatelyelevated temperatures. It is also more economical than horse hair, andrelated materials, and is readily available in increasing quantities.Furthermore, this material can be produced in any diameter and lengthdesired and may readily be made either straight or curled.

"ice

}Eor.p urposes of. the present invention the .curled extruded caseinfiber of monofilament vtype is. particularlysuitable. .Filamentswhichhave been tested for purposes of...the presentinvention have. thefollowing characteristics:

Tenacity 0.5-1.0.g./denier. Tensile strength 8,500-l6,000 p. s. i.Impactstrength 50-100 ft.lbs./sq. in. Knot strength 5,000 7,'500/sq. imDiameter range; .0.005..0.l6", 145-1330 denier. Elongation at break.2025%. Specific-gravity 1.29. Moisture-Regain:

65%" RH: 70F 10-15.%. 20% RH 70 F 6.5%. Burning rate Very slow.Resistance: to heat Some damage. starts at 210 F. Resistance to abrasionGood. Elastic recovery; Excellent. Solubility inorganic solvents.--Insoluble. Color range Unlimitedtnat. color white).

Resistance to mold, mildew and Resistant.

- moths.-

,It will be seen from the foregoing that the curled casein monofilarnentof the type described .above isparticularly suitableforuse in typicaliournal'bearings where there is. freqnentlysome temperature elevation. Apar- Iticular' filament which ,is.quite satisfactory is one which issold under the; trade name Caslan This Casla'n fiberi's-becorningincreasingly available and can readily .flbe stranded withreclaimed wool, wool yarn or other available types of fiber.

Itis preferred to combine the wool fiber and the .casein. fiber inproportions of about wool (such as shredded carpet waste, for example)with about 25'% by .to have asubstantial. portion of the finerwool'fiber presentlfor better. wicking or capillary feed of thelubricant.

The lubricatingingredient itself'is. preferably a lubrieating grease ofsoft consistency although an oil' without a special thickener can beused in many applications. The composition presently preferred includes75 to 95% by weight of calcium soap-mineral oil lubricating grease. Sucha grease may contain from 3 to 20% of calcium soap of higher fatty acidssuch as the C12 to C22 saturated and unsaturated fatty acids. The soapmay be prepared, of course, from substituted acids such as' keto andhydroxy acids, for example, 4-keto-stearic acid or l2-hydroxy stearicacid, instead of fatty acids or in admixture therewith, if desired.Mixtures of soaps may be used andthe soaps of other metals such assodium, potassium, lithium, or aluminum may be employed. The calciumsoap greases are usually less expensive and have a desirable consistencyat usual journal beating temperatures and they are normally preferred.Complex soaps of the soap-salt type may be used when high temperaturegrease stability is important.

Several examples were prepared in order to test out the invention. Thefirst consisted of by weight of a standard lime soap grease having asoap content of about 10 to 12% by weight. This is a soft, smooth,nonfibrous grease composition. To this was added 15% by weight, based onthe total composition, of a mixture of wool waste obtained from shreddedcarpet and ordinary horse hair, the mixture containing about 25% horsehair and 75% wool.

A second sample was prepared exactly as in the first except 1 that a.monofilament casein fiber (curled Caslan was employed in lieu'of thehorse hair.

. A third sample was prepared as in the case of Sample 2except that theCaslan fiber was reduced to 90% 'ot the fiber being wool waste.

A fourth sample consisted of 85% of the same lime soap grease as inSample 1 with of a blended fiber which contained 75% of long strand woolyarn and 25% Caslan fiber.

A fifth sample was the same as the fourth except that the Caslan fibercontent was reduced to 10% of the total fibrous material.

It was observed in tests in journal bearings that 10% by weight of theCaslan was fully equivalent to 25 S. S.'U-. at 210 VP.) for 3 months ata temperature which ranged between 150 and 250 F. There was no appar entdeterioration of the Caslan fiber at the end of the test period. Alsothere did not appear to be any loss in elasticity over this extendedperiod at the relatively high temperature range of 150 to 250 F. It willbe appreciated that any fiber which tends to break down or becomebrittle at an operating temperature is quite unsatisfactory forindustrial purposes. Even while being lubricated the journal bearings ofrailroad cars, for example, frequently become quite hot (200 F. or so)due to the heavy application of brakes to the wheels on long grades. Thefibrous lubricating compositions of the present invention aresubstantially less susceptible to elastic deterioration at elevatedtemperatures than those of the prior art. They can be more closelycontrolled to obtain a desired degree of elasticity which may bemaintained over a relatively long period of time. At the same time theyare substantially less expensive than prior art compositions includinghorse hair. They are much more satisfactory in their resistance topacking or matting than standard fibrous lubricants which do not containan elastic fiber.

It will be obvious that various types of oil, synthetic as well asmineral, may be used and that various thickeners may be used such as areused in the production of and the like maybe incorporated'as will bereadily apparent to those skilled in the art.

What is claimed is:

1. An elastic fiber lubricant composition comprising a major proportionby weight of a lubricating grease and a minor proportion by weight of afibrous mass comprising a major proportion of a mildly elastic woolfiber and about 10 to 40% by weight of a. highly elastic extrudedmonofilament curled casein fiber, which has strong resistance againstmatting at temperatures up to at least 200 F.

2. An elastic fiber lubricant composition comprising to by weight ofcalcium soap-mineral oil lubricating grease and a fibrous masscomprising a major proportion of a relatively fine fiber wool waste,which has a tendency to become matted, and a minor proportion of arelatively coarse highly resilient extruded monofilament curled caseinfiber suflicient to overcome said matting tendency.

3. Composition according to claim 2 wherein the casein fiber comprises10 to 25% of the fibrous mass and is substantially un about 210 F.

v 4. An elastic fiber lubricant composition consisting essentially of afibrous mass impregnated with an oily lubricant, said mass comprising amajor proportion of a W001 fiber, which has a tendency to become matted,and a minor proportion of a curled, relatively coarse elastic extrudedmonofilament casein fiber interspersed through said mass to overcomesaid matting tendency.

5. Composition according to claim 4 wherein the oily lubricant is acalcium soap thickened mineral base lubricating oil.

References Cited in the file of this patent UNITED STATES PATENTS915,804 Stcarns Mar. 23, 1909 1,001,371 Drury Aug. 22, 1911 1,564,306Fantz Dec. 8, 1925 2,342,994 Atwood Feb. 29, 1944 OTHER REFERENCESKlemgard: Lubricating Greases, Published 1937 by Reinhold PublishingCorp., 330 W. 42nd St., New York, N. Y., USA. Page 324.

Ser. No. 96,470, Ferretti (A. P. C.), published April 27, 1943.

ected by heat up to a temperature of.

1. AN ELASTIC FIBER LUBRICANT COMPOSITION COMPRISING A MAJOR PROPORTIONBY WEIGHT OF A LUBRICATING GREASE AND A MINOR PROPORTION BY WEIGHT OF AFIBROUS MASS COMPRISING A MAJOR PROPORTION OF A MILDLY ELASTIC WOOLFIBER AND ABOUT 10 TO 40% BY WEIGHT OF A HIGHLY ELASTIC EXTRUDEDMONOFILAMENT CURLED CASEIN FIBER, WHICH HAS STRONG RESISTANCE AGAINSTMATTING AT TEMPERATURES UP TO AT LEAST 200* F.